1. Field of the Invention
The present invention relates to a valve for opening and closing a conduit (passage) of fluid (liquid or gas). More specifically, the present invention relates to an apparatus with which the operational status of a stop valve can be visually checked, and also relates to an apparatus with which a normally-closed valve can be manually opened.
2. Description of the Related Art
Various types of stop valves having a structure in which a valve element is normally biased in an opening or closing direction by a spring force so that an associated conduit is closed or opened when the valve element is acted upon by the pressure of a working fluid against the spring force are known in the art. However, in such types of conventional stop valves, the only way to check the operational status of the stop valve is to read a gauge, e.g., a flowmeter, or a pressure gauge.
Furthermore, various types of normally-closed valves having a structure in which a valve element is normally closed by a spring force so that the associated conduit is opened when the valve element is acted upon by the pressure of a working fluid against the spring force are known in the art. In such types of conventional normally-closed valves, under conditions which disallow the valve to be supplied with any working fluid, it is difficult to open the valve in the case where the value needs to be opened. Specifically, in a normally-closed valve whose pressure for closing the valve is high (i.e., the spring force for closing the value is great), it is more difficult to open the valve when it needs to be opened under the same conditions, and moreover, it is extremely difficult to adjust and maintain the opening state (open width) of the valve.
An object of the present invention is to provide an apparatus having a simple structure with which the operational status of a stop valve (e.g., whether the valve is open or closed) can be visually checked. Another object of the present invention is to provide an apparatus with which a normally-closed valve can be manually opened, and which makes it possible to adjust and maintain the opening of the valve easily.
To achieve the object mentioned above, a stop valve is provided, including a working rod for operating a valve element which is moved to close and open a main conduit; a biasing member which biases the working rod in a direction to make the valve element one of close and open the main conduit; a piston body which is coupled to the working rod and slidably fitted in a housing of the stop valve; a pressure chamber formed within the housing by the piston body; a pressure supplying device which supplies a working fluid to the pressure chamber to move the working rod in a direction against a biasing force of the biasing member; and a visual checking member which is integral with the working rod to project from the housing in accordance with movement of the working rod, wherein an amount of projection of the visual checking member varies in accordance with an axial position of the working rod.
Preferably, the visual checking member fully retreats into the housing when the working rod is in one of a valve-open position and a valve-closed position, and the visual checking member projects from the housing when the working rod is in the other of the valve-open position and the valve-closed position.
In an embodiment, the visual checking member is formed as a cylindrical member which is coaxial to the working rod. The working rod includes a control conduit which is connected with the pressure chamber, and an external tube is connected to the working rod to be positioned in the visual checking member and to be connected with the control conduit.
Preferably, a cylindrical holder is further provided, which is coaxially fixed to the working rod, wherein the visual checking member is formed as a cylindrical member, and is fixedly attached to the cylindrical holder.
In an embodiment, the biasing member biases the working rod in the first direction to make the valve element close the main conduit. The stop valve further includes a hand-operated valve opening jig which includes a manual-opening attachment which can be detachably attached to the cylindrical holder, and an operational member which is operated to move the working rod in a direction to make the valve element open the main conduit via the manual-opening attachment.
Preferably, a hand-operated valve opening jig is further provided, which includes a rotational member having a cylindrical surface which comes into contact with an operational mount mounted on the housing, the rotational member being pivoted about the manual-opening attachment via a pivot provided at a position which deviates from an approximate center of the cylindrical surface toward the cylindrical holder, and an operational member which is operated to couple the manual-opening attachment to the cylindrical holder, and is operated to rotate the rotational member with the cylindrical surface contacting the operational mount.
In an embodiment, the hand-operated valve opening jig includes a locking shaft which is screwed into the rotational member so that a tip end of the locking shaft can be engaged with a stopper surface formed on the manual-opening attachment. The stopper surface is formed so that a distance between the stopper surface and the tip end of the locking shaft increases as the cylindrical holder is moved in a valve-opening direction via the manual-opening attachment and the pivot when the rotational member is rotated with the cylindrical surface thereof remaining in contact with the operational mount, and the distance varies in accordance with an amount of screw-engagement of the locking shaft with respect to the rotational member.
Preferably, the locking shaft is formed integral with the operational member.
In an embodiment, the hand-operated valve opening jig includes a rotational member having a cylindrical surface which comes into contact with an operational mount mounted on the housing, the rotational member being pivoted about the manual-opening attachment via a pivot provided at a position which deviates from an approximate center of the cylindrical surface toward the cylindrical holder; a locking arm which is pivoted within the rotational member, wherein one end of the locking arm can be engaged with the stopper surface of the manual-opening attachment; and a spring which biases the locking arm so that the one end of the locking arm is biased in a direction to be engaged with the stopper surface of the manual-opening attachment. The stopper surface is formed so that a distance between the stopper surface and the pivot point of the locking arm increases as the cylindrical holder is moved in a valve-opening direction via the manual-opening attachment and the pivot when the rotational member is rotated with the cylindrical surface thereof remaining in contact with the operational mount, and a distance between the one end of the locking arm and the stopper surface increases if the locking arm is rotated manually against spring force of the spring.
Preferably, the operational lever is fixed to the rotational member in order to manually rotate the rotational member, the locking arm being positioned in the operational lever.
In an embodiment, the stop valve includes a power-assisted device with which the biasing force of the biasing member is multiplied to be transmitted to the working rod.
Preferably, the visual checking member is colored.
Preferably, the stop valve further includes a stationary bearing member which is provided in the housing, wherein the piston body and the working rod are relatively movable with respect to the stationary bearing member; a gap formed between the piston body and the stationary bearing member via which the working fluid is supplied to the pressure chamber; at least one slit formed on the stationary bearing member to be connected with the gap so that the working fluid is supplied to the pressure chamber via the gap and the at least one slit; and a sealing member supported by the piston body, wherein the sealing member opens one end of the gap to make the pressure chamber connect with a control conduit via the gap and the at least one slit when the piston body is positioned at a limit of a movable range thereof due to the biasing force of the biasing member, and wherein the sealing member closes the one end of the gap to make the pressure chamber connect with the control conduit via only the at least one slit when the piston body moves from the limit of the movable range, wherein the pressure chamber is defined by the piston body, the housing and the stationary bearing member.
Preferably, the sealing member is formed as an annular sealing member which is fitted in an annular groove formed on an inner peripheral surface of the piston body to face the gap.
Preferably, the stop valve further includes a line joint which is positioned in the visual checking member and coupled to the working rod to be connected with the control conduit, one end of the external tube being connected to the working rod via the line joint.
According to another aspect of the present invention, an apparatus is provided for manually opening a normally-closed valve, the apparatus including the normally-closed valve and a hand-operated valve opening jig. The normally-closed valve includes a working rod for operating a valve element which is moved to close and open a conduit; a cylindrical holder which is coaxially fixed to the working rod, and to which the hand-operated valve opening jig can be detachably attached from the outside of the housing; a biasing member which biases the working rod in a first direction to make the valve element close the conduit; and a pressure chamber which is formed within the housing, and is supplied with a working fluid to move the working rod in a second direction to make the valve element open the conduit. The hand-operated valve opening jig includes a manual-opening attachment which can be detachably attached to the cylindrical holder; a rotational member having a cylindrical surface which comes into contact with an operational mount mounted on the housing, the rotational member being pivoted about the manual-opening attachment via a pivot provided at a position which deviates from an approximate center of the cylindrical surface toward the cylindrical holder; and an operational member which is operated to couple the manual-opening attachment to the cylindrical holder, and is operated to rotate the rotational member with the cylindrical surface contacting the operational mount.
In an embodiment, the hand-operated valve opening jig includes a locking shaft which is screwed into the rotational member so that a tip end of the locking shaft can be engaged with a stopper surface formed on the manual-opening attachment. The stopper surface is formed so that a distance between the stopper surface and the tip end of the locking shaft increases as the cylindrical holder 51 is moved in a valve-opening direction via the manual-opening attachment and the pivot when the rotational member is rotated with the cylindrical surface thereof remaining in contact with the operational mount, and wherein the distance varies in accordance with an amount of screw-engagement of the locking shaft with respect to the rotational member.
Preferably, the locking shaft is formed integral with the operational member.
In an embodiment, the hand-operated valve opening jig includes a locking arm which is pivoted within the rotational member, wherein one end of the locking arm can be engaged with the stopper surface of the manual-opening attachment; and a spring which biases the locking arm so that the one end of the locking arm is biased in a direction to be engaged with the stopper surface of the manual-opening attachment. The stopper surface is formed so that a distance between the stopper surface and the pivot point of the locking arm increases as the cylindrical holder is moved in a valve-opening direction via the manual-opening attachment and the pivot when the rotational member is rotated with the cylindrical surface thereof remaining in contact with the operational mount, and wherein a distance between the one end of the locking arm and the stopper surface increases if the locking arm is rotated manually against spring force of the spring.
In an embodiment, the hand-operated valve opening jig further includes an operational lever fixed to the rotational member for manually rotating the rotational member, the locking arm being positioned in the operational lever.
In an embodiment, the stop valve includes a power-assisted device with which the biasing force of the biasing member is multiplied to be transmitted to the working rod.
According to another aspect of the present invention, a stop valve is provided, including a working rod for operating a valve element which is moved to close and open a conduit; a biasing member which biases the working rod in a first direction to make the valve element close the conduit; a pressure chamber formed within a housing of the stop valve; a pressure supplying device which supplies a working fluid to the pressure chamber to move the working rod in a second direction against a biasing force of the biasing member; and a moving member which moves together with the working rod to project out of and retreat into the housing in accordance with movement of the working rod.
According to another aspect of the present invention, a stop valve is provided, including a working rod for operating a valve element which is moved to close and open a conduit; and a moving member which moves together with the working rod so that the moving member retracts into a housing of the stop valve when the valve element is moved to close the conduit and so that at least part of the moving member projects out of the housing when the valve element is moved to open the conduit.
The present disclosure relates to subject matter contained in Japanese Patent Applications Nos. 2000-85970 (filed on Mar. 27, 2000), 2000-397802 (filed on Dec. 27, 2000) and 2000-397803 (filed on Dec. 27, 2000) which are expressly incorporated herein by reference in their entireties.